The present invention relates to an actuating system for controlling the carburetor of an internal combustion engine, and more particularly to a dual carburetor system for a V-engine in which carburetors for the cylinders are positioned side by side in a V-shaped space between the cylinders, and in which the valve stems of the throttle valves for the cylinders are rotated simultaneously to open and close the throttle valves of the carburetors in unison.
In a V-engine, generally speaking, it is customary for a caburetor to be positioned in the V-shaped space between cylinders so as to make the external shape of the V-engine compact, such as in a motorcycle. According to this positioning, a V-shaped engine is equipped with a separate carburetor for the cylinders on each side with the drafting directions of the respective caburetors opposite to each other. Therefore, if the respective caburetors used are to have the same specifications, it becomes necessary to make their throttle valve stems so coactive that they are rotated in opposite directions. In other words, if the same carburetor design is to be used for both sides of the V-engine, one must be turned 180.degree. so that its valve stems must rotate in a direction opposite to the other. That then presents a problem in rotating both valve stems in unison.
This problem has been solved according to the prior art by providing a separate throttle-actuating cable for each carburetor and connecting both to the same control member, such as the accelerating grip of a motorcycle. However, the throttle cables of the respective carburetors tend to stretch differently so that in time the output power of the respective cylinders become unequal thereby causing undesirable engine vibration and interference between cylinders in engine exhaust operation. It is therefore necessary for the coactions of the throttle valve stems to be ensured by means of a linkage.
The present invention has been conceived in view of the requirement for dual carburetors thus far described, and has as an object to make such a dual carburetor as compact as possible, yet capable of being assembled, and operated reliably without any difference between caburetors even though there is significant offset between the throttle valve stems of the carburetors.